Oxo-degradable projectiles containing pheromones

ABSTRACT

The invention relates to paintball-pellet-type projectiles containing insect pheromones encapsulated in an aqueous oil-in-water-type formulation. Said formulations can release said pheromones in a sustained manner. Said projectiles are characterised in that they contain the aqueous formulation of encapsulated pheromone compatible with the envelope of the projectile composed of oxo-degradable polymer. The aim of the invention is to use said projectiles to treat trees against insect pests by spraying and bursting said projectiles on the trunks of said trees.

INTRODUCTION

The present invention relates to the production and use of paintballtype projectiles containing pheromones such as the pheromones ofprocessionary caterpillars, encapsulated in an emulsion type aqueousformulation. Said formulations are capable of releasing said pheromonesin a prolonged manner. Said projectiles have the feature of containingan encapsulated aqueous formulation of pheromone compatible with theprojectile shell composed of oxo-degradable or oxo-biodegradablepolymer. Another object of the invention is the use of these innovativesystems for treating forests or orchards against insect pests via thesexual confusion technique.

PRIOR ART

The use of pheromones for controlling insect populations in agricultureor forestry is well-known to those skilled in the art. A pheromone is achemical substance produced by an animal and which is a stimulus forindividuals of the same species or of another species. Pheromones canthus be produced either by living organisms or artificially by chemicalsynthesis.

The mechanism of action of pheromone-based treatments is either to guidethe insects toward an insect trap or to introduce sexual confusion bysaturating with pheromones the insects' antennae, which normally enablea male to find females (or vice versa) (Behavior—modifying chemicals forinsect management: applications of pheromones and other attractants,Chapter 4 edited by Richard L. Ridgway, Robert M. Silverstein, May N.Inscoe).

In the case of arboriculture, the usual techniques for spreadingpheromones are wick bottles, programmable vaporizers, orpheromone-soaked strips suspended from the branches. By way of example,mention may be made of wick bottles such as those sold under theRhynchotrak® or Rhyncopro® brands, plastics (Cosmotrack®) or gets soakedwith the pheromone-containing substance (for example US 20110014257 orU.S. Pat. No. 8,828,374 B2), porous plastic capsules (BASF products forexample sold under the Rak® brand) or programmable vaporizertechnologies (US 2008/0184614, or the product Checkmate®). Althoughinteresting, these techniques have many drawbacks, including theirimplementation costs (which includes installing and removing diffusers)and their production costs. Moreover, in the case of forestry, problemsrelated to ease of installation become even more obvious due to treeheight and the difficulty of accessing certain locations.

Other techniques have thus been envisaged, such as aerial application ofmicroparticles (U.S. Pat. No. 6,540,991) or the use of projectileslaunched into tree branches. The latter techniques are promising butmeet objections in terms of respect for the environment.

For example, in 1974, James C. Hale had the idea of using pistol orrifle type projectile launching systems for marking trees (U.S. Pat. No.3,788,298). Several proposals were then made to adapt that technique fortreating forests with pesticides or pheromones against forest pests,with notably the development of various types of projectiles:projectiles connected by a spring as in U.S. Pat. No. 8,561,343,projectile or explosive cartridges having one or two compartments asdescribed in U.S. Pat. No. 6,772,694B1 or US 200606518A1. Indeed, one ofthe major difficulties in designing projectiles suitable for a launchersuch as a compressed-air pistol or rifle is that the “bullets” must besimultaneously sufficiently resistant, chemically compatible with theircontents (pheromone or pesticide-based composition), and easily rupturedupon impact. Thus, the projectiles used often consist of a gelatin shell(patent US20020061325 A) which is incompatible with pheromonecompositions containing water (problem of the gelatin shell softening inthe presence of an aqueous medium, thus making projection of the shellmechanically impossible). Document US20020061325 specifically statesthat the gelatin shells are intended to contain hydrophobic fillmaterials due to this incompatibility with water-based orwater-containing fill compositions. Storage and transport ofgelatin-shell projectiles are thus problematic because they should notbe exposed to moisture, which means that they must be stored andtransported in heat-sealed airtight packaging. Although many suchcompositions lend themselves to a paintball type leisure use where thecontents of the bag, once opened, are quickly used due to the firingrate, for forest tree marking applications the ambient moistureassociated with a much lower rate leads to degradation of the shell dueto softening.

However, the advantage of aqueous formulations for gradually releasingpheromones is significant because they are environmentally friendly. Ifthe microparticle matrix is itself biodegradable, the whole system(shell and aqueous formulation) is itself biodegradable, which makes itsuited to use in the natural environment. In addition, if a solventother than water was used, its evaporation into the air would lead toatmospheric pollution unsuited to the intensive treatment of forestsinfested by defoliating insects, for example.

Certain biodegradable shells have been studied in the past. For example,keratin has been proposed to form the shell of projectiles containing adisinfectant in the case of the pine processionary (patent WO2008/065218). However, apart from the fact that no example of aqueouscontent is provided, recent work (in particular that of the INRA), showsthat keratin is difficult to transform for the industrial production ofprojectiles that could be filled with an aqueous formulation ofpheromone.

In addition, in patent FR 200951799, D. Delhaye describes a paintballsystem characterized in that the paintball shells are composed of anoxo-biodegradable polymer. That material is a polymer containingtransition metals which, under the joint action of oxygen from the airand UV radiation, will degrade the polymer into micro-sized pieceswhich, in the case of polyolefins, will become biodegradable. Suchshells are designed to convey fertilizers and insecticidal or plantprotection products which are in liquid form and compatible with theshell material.

The existing solutions are unsatisfactory for dispersing pheromonesincompatible with oxo-degradable materials. Moreover, a liquidformulation leads to spatter upon impact and bursting and a significantloss of active material. The inventors have therefore designed aqueousformulations of pheromones which are compatible with oxo-biodegradablepolymer projectile shells and which release insect pheromones forseveral months, making it possible to induce sexual confusion in forestor orchard insect pests.

DESCRIPTION OF THE INVENTION

The applicant has thus developed a new type of projectile, representedin FIG. 1, which is capable of treating trees against insect invasions

Thus, in a first embodiment, the present invention concerns a projectilecomprising a shell and a fill material characterized in that the shellcomprises an oxo-degradable thermoplastic polymer or copolymer and inthat the fill material consists of an aqueous formulation of“oil-in-water” emulsion type wherein the aqueous phase comprises agelling agent and the oil phase comprises a matrix consisting of amixture of oil and/or wax and pheromone.

In a second embodiment, the projectile according to the invention ischaracterized in that the oxo-degradable thermoplastic polymer orcopolymer of the shell is selected from the group consisting ofoxo-degradable polyolefins.

Preferentially, the oxo-degradable thermoplastic polymer or copolymer isselected from the group consisting of oxo-degradable polyethylene andoxo-degradable polypropylene.

In another embodiment of the present invention, the projectile ischaracterized in that the emulsion of the aqueous formulation comprises20 to 70 wt. % aqueous phase and 80 to 30% oil phase.

The projectile according to the invention, in another embodiment of theinvention, is characterized in that the gelling agent is selected fromthe group consisting of cellulose ethers, polyurethanes and copolymersof (meth)acrylic acid and ethyl acrylate.

Particularly, the projectile according to the invention is characterizedin that the gelling agent is a copolymer of (meth)acrylic acid and ethylacrylate comprising:

-   -   30 to 40 wt. % methacrylic acid    -   45 to 60 wt. % ethyl acrylate    -   5 to 20 wt. % macromonomer of general formula (I):

-   -   where m is an integer from 1 to 40, preferably from 10 to 30,        and where R is a group of general formula C_(n)H_(2n+1) wherein        n is an integer from 9 to 25, preferably from 10 to 20, and more        preferentially equal to 12; the pH of the aqueous phase is from        5 to 8.

In a particular embodiment of the invention, the projectile according tothe invention is characterized in that the oil phase comprises from 0 to90 wt. % wax, particularly from 10 to 80 wt. % wax, from 0.1 to 25 wt. %pheromone and from 0 to 90 wt. % oil, particularly from 10 to 80 wt. %oil and 0 to 0.8 wt. % stabilizer, antioxidant and anti-UV.

According to another embodiment of the invention, the pheromone of theprojectile is selected from the group of fatty-chain pheromones ofinsects, in particular a sex pheromone of pine processionary moths, oakprocessionary moths, box tree moths, silk moths and codling moths.

It is also another object of the present invention to provide aprojectile as defined above, characterized in that the weight ratio ofshell to fill material is 1:20 to 1:200.

Also, in an embodiment of the invention, the projectile is characterizedin that the thickness of the shell is 50 to 500 μm, preferentially 80 to250 μm.

In a particular embodiment of the invention, the projectile ischaracterized in that it is a sphere having a diameter of 0.5 to 5 cm,preferably of 1 to 3 cm.

In order to ensure satisfactory spreading upon impact, the projectileaccording to one of the variants of the invention is characterized inthat the viscosity of the aqueous formulation of fill material is from1000 to 15000 centipoises at 25° C., particularly from 2000 to 10000centipoises at 25° C.

In another embodiment, the projectile according to the invention ischaracterized in that the weight ratio of oil and/or wax to pheromone inthe oil phase is from 70:30 to 99.5:0.5, more particularly from 80:20 to98:2.

The present invention also concerns the use of a projectile according toone of the embodiments described herein for protecting a stand of treesagainst an insect pest characterized by the fact that the projectile isprojected and bursts on the trunk of the trees of the stand to beprotected. In particular, the projectile is projected with sufficientforce to cause the shell to burst and to cause all or part of the fillmaterial to adhere to the trunk.

The use of a projectile according to the invention as described is alsocharacterized in that the insect pest is selected from the groupconsisting of the pine processionary moth, the oak processionary moth,the box tree moth, the silk moth and the codling moth.

Lastly, in a particular embodiment of the invention, the use of theprojectile as described is characterized in that said projectile isprojected and bursts at the canopy level.

Thus, the projectile according to the invention comprises a shell and afill material and is characterized in that the shell comprises anoxo-degradable thermoplastic polymer or copolymer and the fill materialcomprises an aqueous formulation of “oil-in-water” emulsion type whereinthe aqueous phase comprises a gelling agent and the oil phase comprisesa matrix consisting of a mixture of oil and/or wax and pheromone.

The aqueous formulation of the projectile is capable of slowly releasingpheromones and resisting washing-off due to the elements, in order tocontrol the behavior of insects or animals.

The projectile can have a spherical, ovoid, cylindrical or conical shapeor any other molded shape. Preferably the projectile is a sphere havinga diameter of 0.5 to 5 cm, particularly of 1 to 3 cm in diameter.

The projectile shell consists of an oxo-degradable or oxo-biodegradablethermoplastic polymer or copolymer, preferably oxo-degradable oroxo-biodegradable polyethylene or polypropylene.

The expression “thermoplastic” refers to a material that softensrepeatedly when heated above a certain temperature, but that hardensagain below that temperature. Such a material will thus alwaysreversibly retain its initial thermoplasticity.

The expression “oxo-degradable” or “oxo-biodegradable” refers to apolymeric material that can degrade biologically in nature, after havingfirst undergone abiotic oxidative degradation under the combined effectsof heat and UV, by oxidation of carbon-hydrogen bonds, which lowers thematerial's molecular weight. The material oxidized in the presence ofmicroorganisms is then converted to CO₂, water and non-sterile biomass,without generating toxic residues.

The fill material of the projectiles according to the inventioncomprises, or consists of, an aqueous formulation which slowly releasesthe pheromones. Said aqueous formulation comprises, or consists of, anoil-in-water type emulsion which comprises from 20 to 70 wt. % aqueousphase and 80 to 30 wt. % dispersed oil phase comprising, or consistingof, a matrix based on biodegradable natural wax and/or natural oil inwhich are incorporated the pheromones for controlling insect behavior.

The stability of the emulsion of the aqueous phase is provided by thepresence of a water-soluble gelling agent or rheology modifier. Thegelling agent, or rheology modifier, helps to increase the viscosity ofthe aqueous phase of fill material so that the latter does not scatterwhen the projectile bursts upon impact. The nature of the water-solublegelling agent is not critical insofar as it is compatible with thedesired viscosity and the pheromone contained in the oil phase. Thewater-soluble gelling agent or rheology modifier may be selected frompolysaccharides or from the group consisting of cellulose ethers,polyurethanes, and HASE type copolymers.

Examples of cellulose ether include methyl cellulose, hydroxymethylcellulose, hydroxyethylcellutose, hydroxypropylcellulose, hydroxyethylmethyl cellulose, hydroxypropyt methyl cellulose andcarboxymethylcellulose.

It should be recalled that hydrophobically modified alkali-swellableemulsion (HASE) type polymers are copolymers of (meth)acrylic acid andalkyl acrylate produced by radical polymerization in emulsion and whichhave the property when neutralized by a base such as soda or ammonia tobecome water-soluble and to modify the rheology of the water, but whosecomposition further comprises hydrophobic macromonomers of generalformula:

Where m is an integer from 1 to 40, in general greater than 5, and whereR is a group of general formula C_(n)H_(2n+1) wherein n is an integerfrom 10 to 30, particularly from 9 to 25, more preferably from 10 to 20.They also have the capacity to modify the rheology of the aqueoussolution.

They are prepared according to methods well-known to those skilled inthe art by means of a mercaptan type chain-transfer agent.

The amount of water-soluble gelling agent in the aqueous phase can befrom 5 wt. % to 20 wt. %. Particularly, from 5 to 10 wt. % of theaqueous phase. The amount of said water-soluble gelling agent can beadjusted as a function of its nature and gelling power, and this inorder to obtain the desired viscosity for the aqueous formulation offill material of the projectiles according to the invention.

Preferentially, the gelling agent is an acrylic copolymer, in particulara HASE type acrylic copolymer, and is characterized in that it contains:

-   -   30 to 40 wt. % methacrylic acid,    -   45 to 60 wt. % ethyl acrylate,    -   5% to 20 wt. % macromonomer of general formula (I):

Where m is an integer from 1 to 40, preferably from 10 to 30, and whereR a group of general formula C_(n)H_(2n+1) wherein n is an integer from9 to 25, preferably from 10 to 20, and more preferentially equal to 12.

If an acrylic copolymer, in particular a HASE type acrylic copolymer asdefined above, is used as water-soluble gelling agent, the amountthereof in the aqueous phase can be from 5 to 15 wt. %, moreparticularly from 5 to 10 wt. %. In order to obtain the desiredviscosity, the pH of the aqueous phase will be from 5 to 8, particularlyfrom 6 to 8, in order to ensure the gelation of said copolymer and toreach the desired viscosity.

The dispersed oil phase of the emulsion comprised in the aqueousformulation of fill material of the projectiles according to theinvention comprises from 10 to 90 wt. % wax, particularly from 60 to 80wt. % wax, 10 to 90 wt. % oil, particularly 8 to 35 wt. % oil, 0.1 to 25wt. % pheromone, particularly from 0.5 to 20 wt. % pheromone, and from 0to 0.8 wt. %, particularly from 0.1 to 0.5 wt. % stabilizer.

For the purposes of the invention, the term “wax” means a lipophiliccompound which is solid at room temperature (about 25° C.) andatmospheric pressure (760 mmHg). The waxes that can be used in acomposition according to the invention may be selected from waxes ofanimal, vegetable, mineral or synthetic origin and mixtures thereof. Inparticular, use can be made of hydrocarbon waxes such as beeswax,lanolin wax and Chinese insect waxes; rice wax, carnauba wax, candelillawax, jojoba wax, ouricury wax, esparto wax, cork fiber wax, sugar canewax, Japanese wax and sumac wax, montan wax, microcrystalline waxes,paraffins and ozocerite; polyethylene waxes, waxes obtained byFischer-Tropsch synthesis and waxy copolymers and esters thereof.Mention may also be made of waxes obtained by catalytic hydrogenation ofanimal or vegetable oils having linear or branched C₈-C₃₂ fatty chains.Among those, particular mention may be made of hydrogenated jojoba oil,hydrogenated sunflower oil, hydrogenated castor oil, hydrogenated copraoil and hydrogenated lanolin oil, di-(trimethylol-1,1,1 propane)tetrastearate. Use may also be made of waxes obtained bytransesterification and hydrogenation of vegetable oils, such as castoroil or olive oil, such as the waxes sold under the names Phytowax ricin16L64® and 22L73® and Phytowax Olive 18L57 by the company SOPHIM.

For the purposes of the invention, the term “oil” means awater-immiscible nonaqueous compound which is liquid at room temperature(about 25° C.) and atmospheric pressure (760 mmHg). The oil according tothe invention can be selected from vegetable oils. Particularly, the oilaccording to the invention will be selected from the group consisting ofsunflower oil, peanut oil, soybean oil, rapeseed oil, corn oil, oliveoil, grape oil, walnut oil, linseed oil, palm oil, coconut oil, arganoil, avocado oil, almond oil, hazel nut oil, pistachio oil, rice oil,cotton seed oil, wheat germ oil, sesame oil, or mixtures thereof.Preferably, the oil is selected as a function of the crop sought to beprotected from insect pests, in particular lepidopterans.

A stabilizer, or a mixture of stabilizers, antioxidant and/or anti UV,can be contained in the fill material of the projectiles according tothe invention in order to protect the components of the oil phase, inparticular the pheromones, from oxidation and/or UV. The stabilizer canbe selected from the group consisting of n-butyl-4-hydroxybenzoate(BHB), tocopherol, ter-butyl-hydroquinone (TBH), n-propyl-gallate (PG),t-butyl-hydroxyanisole (BHA), methyl para-hydroxybenzoate (MHB), N,Ndiethyltoluamide (DT), t-butyl-5 hydroxytoluene (BHT) and α-thioglycerin(TG), nitroxides and alkoxyamines and mixtures thereof. The one or morestabilizers protect the oil, the wax and/or the pheromone from oxidationand/or UV.

The one or more pheromones contained in the projectiles according to theinvention are particularly pheromones of insects, more particularlyfatty-chain pheromones of insects. More particularly, the one or morepheromones are fatty-chain pheromones of lepidopterans. Particularly,the projectiles according to the invention contain sex pheromones oflepidopterans. The sex pheromones of insects such as lepidopterans arecharacterized in that they are composed of mixtures of unsaturatedalcohol-, ester- or aldehyde-terminated fatty-chain molecules.

As pheromone contained in the projectiles according to the invention,mention may be made of the pheromones of box tree moths and codlingmoths, pests to trees such as boxwood, chestnut, walnut, apple, pear.More particularly, the pheromone can be a sex pheromone of pine and oakprocessionary moths. Known for their method of travel in nose-to-tailcolumns, the larvae nest in the needles of various pine species or inthe leaves of oaks, causing significant weakening of the trees. A commoncharacteristic of these pests is that the moths travel in the treecanopy, and it is one of the advantages of the invention to be able toplace pheromone diffusion points in the trees at heights up to severalmeters without needing to transport heavy equipment such as ladders orboom lifts.

The shell of the projectiles according to the present invention providesmechanical resistance during storage, handling and projection, forexample using a paintball type air gun, and also allows, by rupturingupon impact on a hard substrate such as the trunk of a tree, theprojectile to burst and to release the fill material. The weight ratiobetween the shell and the fill material can be selected in order topromote either mechanical resistance or ease of bursting upon impact,and this according to the size of the projectile, the nature of theshell material and the nature of the fill formulation. In this context,the nature of the constituent material of the shell and the dimensionalfeatures thereof, as well as the viscosity of the fill material, aresuch that the impact of a projectile on a hard surface causes the shellto burst and the fill formulation to spread while avoiding spatter.Particularly, the weight ratio of shell to fill material can be 1:20 to1:200.

The thickness of the shell of the projectiles according to the inventionwill depend on the size of the projectile, the weight ratio of shell tofill material, the viscosity of said fill material, and also the natureof the oxo-degradable thermoplastic material.

The thickness of the shell can thus be from 50 to 500 μm, particularlyfrom 80 to 250 μm, more particularly from 100 to 200 μm, for example. Byway of example, for a spherical projectile whose shell material is anoxo-degradable thermoplastic polymer or copolymer such as oxo-degradablepolypropylene, having a size of about 1.75 cm in diameter, the thicknessof the shell is of the order of 120 μm.

Typically, a process for producing the projectiles according to theinvention corresponds to that described in WO2014016510 and comprisesthe following steps: receipt of two sheets of oxo-degradablethermoplastic film, each sheet comprising at least one column of shapedcavities; movement of the two sheets to align the respective cavities ofeach sheet and gapping of the sheets via pairs of bars whichsuccessively clamp the sheets on each side of the pairs of columns ofcavities, filling of the pocket delimited between the two pairs of barswith the fill formulation to fill the cavities and welding of the sheetsaround the cavities to form the projectiles.

In addition to its role as stabilizer, the gelling agent, or rheologymodifier, controls the viscosity of the fill formulation. Duringproduction of the projectiles, the aqueous formulation of fill materialmust be sufficiently liquid to allow filling of the projectiles at highrates. Upon impact on a trunk, it must be sufficiently viscous to ensurethe formation of a film of adequate thickness.

The viscosity of the aqueous formulation of fill material of theprojectile according to the invention is selected so as to besufficiently low to allow easy filling of the cavities of theprojectiles during production thereof but sufficiently high in order tolimit spatter when the projectile bursts upon impact on a hard surface,in particular a trunk. The gelling agent and the amounts of said agent,as well as the conditions suited to the nature of said agent, can beused to determine the viscosity of the aqueous formulation of fillmaterial. Thus, when HASE type copolymers and polymers are used, thegelation thereof being determined by pH, the pH of the aqueous phasewill be from 5 to 8, particularly from 6 to 8, in order to gel saidpolymer. Indeed, as the projectiles according to the present inventionare particularly intended for applying a pheromonal composition on thetrunks of trees, if the viscosity of the fill formulation is too low,spatter is generated when the projectile bursts upon impact, and asignificant portion of said formulation is likely to be lost and fall tothe ground.

The Brookfield viscosity of the aqueous formulation of fill material isthus from about 1000 to about 15000 centipoises, at 25° C., particularly2000 to 12000 centipoises, at 25° C., more particularly 2500 to 10000centipoises, at 25° C. The Brookfield viscosity of the aqueousformulation of fill material can be measured using a Brookfieldviscometer, which consists in the application of a moving force to asubstance—the aqueous formulation—while rotating at fixed speed aspindle of fixed size immersed in said substance. The substance'sresistance to the rotational movement of the spindle is recorded usingan internal spiral spring, then converted to viscosimetric units, forexample centipoises. By way of illustration, the viscosity of theaqueous formulation of fill material of the projectiles according to thepresent invention can be in a range corresponding to that going fromliquid honey to crystallized honey, mayonnaise or chocolate spread, forexample.

The adjustment of the ratio of wax and/or oil to pheromone in the matrixof the oil phase of the emulsion of the aqueous formulation of fillmaterial depends on the solubility of the pheromones in the oil+waxmixture. Said ratio can vary from 70:30 to 99.5:0.5, more particularlyfrom 80:20 to 98:2, even more particularly around 75:25, for example.The projectiles according to the invention are projected against thetree trunks by means of a compressed-air system. The bursting of theprojectile causes the spreading of the aqueous formulation, which formsa film on the trunk surface. Slow release of the pheromone through thefilm thus formed then controls the insects' behavior.

Preferably, the insects targeted by this technology are forest ororchard pests such as the pine processionary or oak processionary, thebox tree moth or silk moths, codling moths (of apple, pear, chestnut,walnut trees, etc.). Projection of the projectiles according to theinvention makes it possible to create within a forest or wooded area asmany pheromone diffusion points as impacts made. A high density ofimpacts, combined with the controlled release of the pheromone by eachdiffuser, creates a pheromone cloud that prevents the insect'sreproduction cycle from occurring properly. This disturbance reduces thepest population and thus protects the trees from the damage causethereby. The impacts will be located preferentially at the canopy leveland their number will be from 100 to 1000 per hectare.

The advantage of the technique developed in the present invention is toallow the treatment of large woodland areas at a controlled cost, altwhile using only biodegradable components containing no organic volatileother than the pheromone itself.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a schematic view of a projectile according to theinvention in which (1) represents the projectile shell made ofoxo-biodegradable thermoplastic material, (2) represents the particlescontaining a mixture of pheromone in a matrix based on wax and/or oiland (3) represents the aqueous phase containing the gelling agent, orrheology modifier.

FIG. 2 represents the demonstration of the degradation of the box treemoth pheromone in the presence of an oxo-biodegradable polymer.

FIG. 3 represents an example of projection of the projectiles ontopines, illustrating the advantage of the system making it possible toplace several diffusers effortlessly.

EXAMPLES

Materials:

The pheromones used in forestry are either purchased from industrialmanufacturers or manufactured by M2i Development (Lacq, France)according to known processes. In the case of the products synthesized byM2i Development, their characterizations are validated by a comparativeanalysis with a referent sample using gas chromatography.

Example 1 (not According to the Invention): Incompatibility of the PurePheromone in Direct Contact with Oxo-biodegradable Materials

The sex pheromone of the box tree moth is the mixture of Z and E-11hexadecenal in a 5:1 ratio.

A paintball projectile shell consisting of an oxo-biodegradablepolyolefin is cut into small pieces of the order of 2 to 5 mm². Thepieces thus obtained are placed in a reactor containing a magneticstirrer. The reactor is placed under nitrogen.

100 mg of the hexadecenal mixture described above is added to the piecesand stirring is maintained until the liquid has been completely absorbedby the pieces.

The pieces are then separated in two portions:

The first half is stored in an aluminum foil pouch, under nitrogen(control). The second half is placed in a closed transparent cup underair in the light. Pieces are regularly analyzed by gas chromatography.Changes in the pheromonal mixture are reported in the following graph(FIG. 2):

FIG. 2 shows that the oxo-biodegradable polyolefin decomposes thepheromone mixture in the presence of oxygen when the latter is in directcontact with the polyolefin. One notes, among other things, theappearance of hexadecenoic acid produced by oxidation of the pheromone.This example illustrates the problem of the compatibility of thepheromones with the oxo-biodegradable polymers and the importance ofprotecting the pheromone in an emulsion as illustrated in the presentinvention.

Example 2: Production of Aqueous Formulations Containing Pheromones

The acrylic rheology modifiers used in the formulations are HASE typeacrylic copolymers provided by the company Coatex (Rheotech® range;France).

The HASE 1 copolymer used for the exemplifications consists of:

35.5 wt. % methacrylic acid,

52.4 wt. % ethyl acrylate,

12 wt. % macromonomer of formula (I) wherein m=30 and n=12.

General Protocol for Producing Aqueous Formulation ContainingPheromones:

-   -   Components of the formulation:

Aqueous phase: HASE1 rheology modifier H₂O 10% NaOH Solution 1 Wax/oilPheromone Stabilizer (BHT) Solution 2 H₃PO₄ (4%)

-   -   Procedure:

Solution 1 is prepared by melting the beeswax, sunflower oil, pheromoneand stabilizer (BHT) mixture at 70° C. in a 4-L jacketed reactorequipped with mechanical stirring (IKA) and a standard anchor orimpeller type stirring rod. The internal temperature of the reactor mustbe higher than the melting point of wax.

In a second jacketed reactor (20 L) equipped with mechanical stirring(IKA) and a standard anchor or impeller type stirring rod, understirring, the aqueous phase is prepared by loading water, soda and therheological additive. This mixture is heated to a temperature higherthan the melting point of wax.

When solution 1 is molten, it is added dropwise to the aqueous phaseusing a Watson-Marlow pump (rotational speed 200) over about 5′.

In order to adjust the viscosity of the prepared formulation, solution 2(phosphoric acid) is finally added dropwise over 15′ with a jackettemperature of 35° C. The medium is stirred for 5′ before being cooledand returned to room temperature

Controlled-release Aqueous Formulation for the Pine Processionary

The aqueous formulation of the pine processionary pheromone was preparedaccording to the general procedure above with the amounts of reagentspresented below.

Test 1 Aqueous phase HASE 1 rheology modifier 1.88 g H₂O 15.48 g NaOH(10%) 0.73 g Solution 1 Beeswax 3.84 g Sunflower oil 11 g Pineprocessionary pheromone 0.46 g Stabilizer (BHT) 0.46 g Solution 2 H₃PO₄(4%) 3.22 g

Example 3: Production of Projectiles According to the Invention Startingwith the Formulations of Example 2

The paintball type projectiles according to the invention were producedby the company Polytek according to the process described in patent WO2014016510 A1 and in the present description. The material used is anoxo-biodegradable polypropylene. The process comprises providing twofilms of similar polymeric material (oxo-biodegradable polypropylene).The fill composition as described above is provided. The films arearranged in an encapsulation unit comprising two molding drums, eachcomprising a cylinder wherein a plurality of hemispherical cavities isformed, said drums being arranged such that axes thereof are paralleland the cylinders are joined, said films feeding continuously in theencapsulation unit so as to arrive tangentially on said cylinders. Thefilms are transformed into capsule portions having a substantiallyhemispherical shape by means of counter-rotating rotation of the moldingdrum cylinders. The fill composition is introduced into said capsuleportions which are joined and closed to form shells filled with thepheromonal composition. The diameter of the substantially sphericalprojectiles obtained is 1.75 cm (68 caliber).

Example 4: Projection of the Projectiles of Example 3 onto Trees

The transfer of material is measured on 10 trunks according to thefollowing protocol:

After 24 h (the time necessary for the water to evaporate), the trunksare scraped to recover the dry deposit and then each sample is dissolvedin hot heptane and filtered so as to eliminate solid particles from thetrunk or shell residues. The heptane is evaporated under reducedpressure and then the residue, which corresponds to the amount ofmaterial transferred during impact, is weighed. This weight is thencompared to the theoretical weight of the matrix and pheromone containedin each projectile (1.01 g).

The results are as follows:

Trunk 1 2 3 4 5 6 7 8 9 10 % transfer 85 86 90 88 91 86 93 90 85 88

Which is on average 88.2% transfer. This shows that the fill material ofthe projectiles according to the invention is nearly completely retainedon the substrate and that very little loss was sustained when theprojectiles burst upon impact on the trunks.

Example 5: Test of Sexual Confusion in a Maritime Pine Stand

500 projectiles containing 1.01 g of oil/wax formulation with a 10% loadof (Z)-13-hexadecen-11-yn-1-ol acetate, a sexual attraction pheromone ofthe pine processionary moth, dispersed in 1.2 g of water and containing3 wt. % HASE 1, were prepared according to example 3.

The 500 projectiles were shot at the pines of a 5-ha stand at a rate of100 projectiles per hectare and at a height of 2.5 m to 5 m. Theshooting grid tends to follow one shot every 10 m as a function of treedensity (FIG. 3).

To monitor population changes on-site, Mastrap L@ type pheromone trapswere placed every 10 m in the middle of the stand. Another 10 traps weredistributed at the periphery of the stand (25 m therefrom). The resultsare as follows:

TABLE 2 number of captures for the 10 traps of each type (these numbersindicate the number of new captures) Inner traps Outer traps T0 + 1month 9 135 T0 + 2 months 11 154 T0 + 3 months 14 122

This example shows the efficacy of the sexual confusion-based protectionsystem according to the invention in protecting against the pineprocessionary moth.

Furthermore, several rainstorms fell on the stand during the test, whichvalidates the resistance of the films deposited on the trunks during thetreatment period.

The invention claimed is:
 1. A projectile comprising a shell and a fillmaterial wherein the shell comprises an oxo-degradable thermoplasticpolymer or copolymer which is selected from the group consisting ofoxo-degradable polyefins, and in that the fill material consists of anaqueous formulation of “oil-in-water” emulsion type wherein the aqueousphase comprises a gelling agent and the oil phase comprises a matrixconsisting of a mixture of oil and/or wax and pheromone.
 2. Theprojectile according to claim 1, wherein the oxo-degradablethermoplastic polymer or copolymer is selected from the group consistingof oxo-degradable polyethylene and oxo-degradable polypropylene.
 3. Theprojectile according to claim 1, wherein the emulsion of the aqueousformulation comprises 20 to 70 wt. % aqueous phase and 80 to 30% oilphase.
 4. The projectile according to claim 1, wherein the gelling agentis selected from the group consisting of cellulose ethers, polyurethanesand copolymers of (meth)acrylic acid and ethyl acrylate.
 5. Theprojectile according to claim 1, wherein the gelling agent is acopolymer of (meth)acrylic acid and ethyl acrylate comprising: 30 to 40wt. % methacrylic acid 45 to 60 wt. % ethyl acrylate 5 to 20 wt. %macromonomer of general formula (I):

where m is an integer from 1 to 40, preferably from 10 to 30, and whereR is a group of general formula CnH2n+1 wherein n is an integer from 9to 25, preferably from 10 to 20, and more preferentially equal to 12;the pH of the aqueous phase is from 5 to
 8. 6. The projectile accordingto claim 1, wherein the oil phase comprises from 0 to 90 wt. % wax,particularly from 10 to 80 wt. % wax, from 0.1 to 25 wt. % pheromone andfrom 0 to 90 wt. % oil, particularly from 10 to 80 wt. % oil and 0 to0.8 wt. % stabilizer.
 7. The projectile according to claim 1, whereinthe pheromone is selected from the group of fatty-chain pheromones ofinsects, in particular a sex pheromone of pine processionary moths, oakprocessionary moths, box tree moths, silk moths and codling moths. 8.The projectile according to claim 1, wherein the weight ratio of shellto fill material is 1:20 to 1:200.
 9. The projectile according to claim1, wherein the thickness of the shell is 50 to 500 μm, preferentially 80to 250 μm.
 10. The projectile according to claim 1, wherein saidprojectile is a sphere having a diameter of 0.5 to 5 cm, preferably of 1to 3 cm.
 11. The projectile according to claim 1, wherein the viscosityof the aqueous formulation of fill material is from 1000 to 15000centipoises at 25° C., particularly from 2000 to 10000 centipoises at25° C.
 12. The projectile according to claim 1, wherein the weight ratioof oil and/or wax to pheromone in the oil phase is from 70:30 to99.5:0.5, more particularly from 80:20 to 98:2.
 13. A method forprotecting a stand of trees against an insect pest wherein a projectileaccording to claim 1 is projected and bursts on the trunk of the treesof the stand to be protected.
 14. The method according to claim 13,wherein the projectile is projected with sufficient force to cause theshell to burst and to cause all or part of the fill material to adhereto the trunk.
 15. The method according to claim 13, wherein the insectpest is selected from the group consisting of the pine processionarymoth, the oak processionary moth, the box tree moth, the silk moths andthe codling moths.
 16. The method according to claim 13, wherein theprojectile is projected and bursts at the canopy level.